Photoarray system construction

ABSTRACT

Embodiments of a photoarray system are provided. In one embodiment, a photoarray system includes an array of lixels, each lixel comprising at least one electrical component supported on a respective platform, each lixel in the array electrically interconnected with at least one adjacent lixel via one or more flexible wires; and heat sink structure supported on each of the platforms for dissipating heat generated by the at least one electrical component, the heat sink structure incorporating strain resistance structure interfacing with, and imparting strain resistance to, the one or more flexible wires.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/931,771 filed on Jan. 27, 2014, the contents of which areincorporated entirely herein by reference.

FIELD OF THE INVENTION

The following relates generally to photoarray systems, and moreparticularly to photoarray system construction.

BACKGROUND OF THE INVENTION

Light therapy involves administering doses of optical radiation to thebody of a recipient of the therapy. Various light therapy systems areknown, including those having one or more radiation sources incorporatedinto a housing that is designed to be held and aimed by a therapist todirect optical radiation towards a patient during a therapy session.Other light therapy systems include a flexible substrate with which isintegrated an array of radiation sources. Such flexible photoarraysystems are designed to conform to a non-planar portion of therecipient's body thereby to enable the radiation sources to be proximateto a region of interest, such as against the recipient's skin, withouthaving to be constantly held in position by the therapist for theduration of a treatment session.

A physically flexible photoarray system is generally intended to bepositioned directly proximate to the body of the recipient of theoptical radiation. With such a configuration, the therapist is notgenerally able to observe the skin or other body surface of therecipient where it is occluded by the flexible photoarray system.Furthermore, a recipient of the light therapy, typically unfamiliar withthe therapy process, may not raise concerns about discomfort or may noteven feel discomfort despite heat levels in various areas between theflexible photoarray system and the recipient's body with which it isdirectly proximate being higher than is healthy for the recipient.Similarly, the therapist and recipient are not typically able tovisually gauge whether an effective amount of radiation has beenadministered to the region of interest.

In addition, it would be useful for a flexible photoarray system to beportable to the extent that it could remain on the recipient,unsupervised by a therapist, for extended periods while the recipient isdoing some other activity. However, facilitating portability andunsupervised use raises unique challenges in how each of powermanagement, heat management, treatment duration and dose monitoring andthe like are addressed.

Furthermore, such a flexible photoarray system that is also intended toconform to the body of the recipient of optical radiation is subject toparticular physical stresses associated both with its flexibility andits portability. Such stresses can lead to early failure of components,which can lead to inoperability of the entire device, and frustration byits users.

SUMMARY OF THE INVENTION

According to an aspect, there is provided a photoarray system comprisingan array of lixels, each lixel comprising at least one electricalcomponent supported on a respective platform, each lixel in the arrayelectrically interconnected with at least one adjacent lixel via one ormore flexible wires; and heat sink structure supported on each of theplatforms for dissipating heat generated by the at least one electricalcomponent, the heat sink structure incorporating strain resistancestructure interfacing with, and imparting strain resistance to, the oneor more flexible wires.

According to another aspect, there is provided a photoarray systemcomprising a control system; a lixel array comprising a plurality oflixels each comprising at least one radiation source that isindividually controllable by the control system to emit radiation; and asensor array comprising a plurality of sensor modules distributedamongst the plurality of radiation sources, each of the sensor modulesconfigured to communicate respective local readings to the controlsystem, wherein each of the radiation sources is supported on arespective platform comprising a circuit board, wherein each circuitboard is interconnected with at least one adjacent circuit board with aplurality of flexible wires.

According to another aspect, there is provided a lixel array for aphotoarray system comprising a plurality of flexibly interconnectedlixels each comprising at least one radiation source, each lixelcomprising a rigid platform for supporting the at least one respectiveradiation source, each platform being configured to be moved withrespect to an adjacent platform between a position in which an edge ofthe platform and a facing edge of an adjacent platform are spaced and aposition in which the edge of the platform and the facing edge are incontact with each other.

Other aspects and advantages will become apparent from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described with reference to the appendeddrawings in which:

FIG. 1 is a schematic diagram of a photoarray system according to anembodiment;

FIG. 2 is a block diagram better illustrating components of a maincontrol module, according to an embodiment;

FIG. 3 is a schematic diagram better illustrating components of acommlink, according to an embodiment;

FIG. 4 is a schematic diagram better illustrating components of a lixel,according to an embodiment;

FIG. 5 is an isometric view of components of a lixel in exploded view;

FIG. 6 is an isometric view of the top of a portion of a series offlexibly interconnected lixels curved inwardly;

FIG. 7 is an isometric view of the top of a portion of a series offlexibly interconnected lixels encased in flexible transparent housing;and

FIG. 8 is an isometric view of the bottom of the portion of the seriesof flexibly interconnected lixels of FIG. 7;

FIG. 9 is an isometric front view of an alternative lixel;

FIG. 10 is a top plan view of the alternative lixel of FIG. 9;

FIG. 11 is an isometric front view of another alternative lixel; and

FIG. 12 is a top plan view of the alternative lixel of FIG. 11.

DETAILED DESCRIPTION

The following description relates to photoarray systems, and descriptionis provided of a photoarray system comprising a granularly controllablelixel array having a plurality of lixels each having one or moreradiation sources. The lixel array of the photoarray system preferablydelivers high power optical energy from the radiation sources in closeproximity over a large epidermal surface area on human or animalpatients. Providing individual control over each of the plurality ofradiation sources facilitates maintaining thermal energy at comfortablelevels for a patient, while facilitating efficient delivery ofelectrically-powered radiation.

In this description, the term “lixel” refers to an electronic modulecomprising one or more radiation sources for emitting non-ionizingradiation such as visible, infrared and/or ultraviolet light and that isindividually controllable to cause its one or more radiation sources tobe actuated.

Turning to FIG. 1, there is shown a schematic diagram of a photoarraysystem 10 according to an embodiment. Photoarray system 10 includes acontrol system A in power and data communications with a lixel array B.

In this embodiment, control system A includes a main control module 100having microcontroller 110, and a radiofrequency transceiver 112configured to provide wireless data communications with an externalcomputing device 1000 such as a desktop computer, a laptop computer, aSmartphone or a tablet having a similar transceiver and equipped tooperate according to standard communications protocols. Such protocolsmay includes WIFI, Bluetooth™, Bluetooth low-energy, ZigBee, ANT, ANT+,MICS, MBAN, MDDS, WMTS, Wireless USB , Z-Wave, 3G, and 4G (LTE) andother hardware/software protocols which may become adopted for short tomedium range wireless communications. For example, main control module100 may be programmed or re-programmed with instructions provided via RFtransceiver 112.

Main control module 100 also includes a power section 114, ahuman/machine interface 116, and a rechargeable battery 118. In thisembodiment, human/machine interface 116 includes touch-sensitivecontrols for actuation and other functions, the operation of which iswell known and will not be described further herein.

Main control module 100 also includes a first power/data interface 120that can be mated with a second power/data interface 220 with which aplurality of communication link modules, or “commlinks” 200 (which arenumbered individually as 200_1, 200_2, 200_3 to 200_x in FIG. 1) ofcontrol system A are in power and data communications. In thisdescription, a commlink 200 is an electronic module that is electricallylinked to both the main control module 100 and a respective lixel orlixels 300 as will be described, and serves an intermediate controlfunction under the control of, and in cooperation with, the main controlmodule 100, as will be described.

In this embodiment, main control module 100 provides power throughpower/data interface 120 along three (3) electrical lines, namely afixed voltage line V_(s) (which would typically be fixed at 5VDC or3.3VDC though other fixed voltages can be used), a variable voltage lineV_(net), and a ground (GND) line. Furthermore, in this embodiment, maincontrol module provides data communications along two (2) lines formingan I²C (Inter-Integrated Circuit) serial data bus, namely a serial clockline (I²C SCL) and a serial data line (I²C SDA).

In this embodiment, lixel array B includes a plurality of lixels 300,each of which are in power and data communications via the three (3)power lines and the two (2) data lines with a respective commlink 200.In particular, each commlink 200_1 . . . 200_x is in power and datacommunications with a respective subset of the plurality of lixels 300.As shown in FIG. 1, commlink 200_1 is in power and data communicationswith each of lixels 300_11, 300_12, . . . 300_1 y, where y is an integernumber representing the number of lixels in power and datacommunications with commlink 200_1. Similarly, commlink 200_2 is inpower and data communications with each of lixels 300_21, 300_22 and soforth, and commlink 200_3 is in power and data communications with eachof lixels 300_31, 300_32 and so forth. The photoarray system 10 may beconfigured to have up to x commlinks 200, each of which (when first andsecond interfaces 120 and 220 are connected) is in power and datacommunications with both the main control module 100 and a respectivesubset of the lixels 300. As such, commlink 200_x is in power and datacommunications with each of lixels 300_x1, 300_x2 and so forth.

The number of lixels 300 that are in power and data communications witha respective commlink 200 is not fixed, and may not be the same acrossall commlinks 200_1 to 200_x. Accordingly, for example, commlink 200_1may be in power and data communications with one number of lixels 300,and commlink 200_2 may be in power and data communications with adifferent number of lixels 300.

FIG. 2 is a block diagram better illustrating components of the maincontrol module 100, which are all housed in a single, preferablywater-tight or water-resistant enclosure, according to this embodiment.In this embodiment, microprocessor 110 is a highly-integrated KinetisARM-based microcontroller package available from Freescale Semiconductorof Austin, Tex., U.S.A. having onboard computer-readable flash systemmemory and non-volatile data memory, in this embodiment SRAM (StaticRandom Access Memory) and NVRAM (Non Volatile Random Access Memory).Stored in the memory devices are temporary data, along withprocessor-readable instructions, baseline protocols and temporaryprotocols for operating the photoarray system 10, along with measurementand reading data from lixels 300 as will be described.Processor-readable data embodying a lixel illumination pattern in theform of tables of electrical current values or similar data may also bestored on main control module 100. Other types of microprocessors couldbe used. Current control, rather than voltage control, is implementedbecause radiation output of the radiation sources is linear with respectto current running through the radiation sources. Microprocessor 110 isin data communications with other components of the main control module100, including RF transceiver 112, human-machine interface 116, powersection 114 having a fixed voltage regulator 114 a, a variable V_(net)voltage regulator 114 b and a battery charger/Coulomb Counter 114 c,rechargeable battery 118, and the first power/data interface 120.Rechargeable battery 118 is in power communications with batterycharger/Coulomb counter 114 c.

A sensor module 119 for the main control module 100 houses one or moreof: an ambient temperature sensor, a motion sensor, a humidity sensor, aphysical orientation sensor, an acceleration sensor, an ambient lightsensor, a magnetic field sensor, a proximity sensor, an audio levelsensor, a video imaging device, an imaging device, one or more coloursensors, or another sensor useful for providing operating andenvironment data.

First interface 120 of main control module 100 is also connectable to anAC (alternating current) adaptor 2000 via an interface 220A thatcooperates with first interface 120 in a similar or the same manner tointerface 220, and directs incoming power V_(CHG) from the AC adaptor2000 to the battery charger/Coulomb counter 114 c for charging therechargeable battery 118. Interface 220A can be configured such thatV_(CHG) can be connected to the V_(net) pin, or to some other pin.

FIG. 3 is a schematic diagram better illustrating components of acommlink 200, according to this embodiment. Commlink 200 receives poweralong respective electrical lines V_(s), V_(net) and GND via itsconnection to main control module 100. Furthermore, commlink 200communicates with main control module 100 via a communication PortI²C_(MCM) along respective I²C serial clock (I²C SCL) and serial data(I²C SDA) lines. Each of commlinks 200_1 to 200_x is individuallyaddressable by main control module 100, and is capable of listening tomessages broadcast on the I²C data bus by the main control module 100 orby other commlinks 200.

Each of fixed voltage line V_(s) and data bus lines I²C_(xy) isconnected to a local microcontroller 210, with fixed voltage line V_(s)being connected to local microcontroller 210 via a voltage regulator212. The voltage regulator 212 is used for implementations in whichmicrocontroller 210 has a different operating voltage than that ofmicroprocessor 310. Microcontroller 210 also includes a separatecommunication Port I²C_(L) to which is connected a second set of databus lines for each of I²C SCL and I²C SDA for its respective lixels 300.It will be noted that lines extending from each of V_(s), V_(net) andGND are run as outputs to commlink 200, with the variable voltage lineV_(netf) (V_(net) “fused”) being run as an output via a fuse 214, andfixed voltage line V_(sf) (V_(s)“fused”) being run as an output via afuse 216.

FIG. 4 is a schematic diagram better illustrating components of thelixel 300, according to this embodiment. Lixel 300 receives power alongrespective electrical lines V_(sf), V_(netf) and GND via lines outputfrom the commlink 200 with which it is respectively in power and datacommunications. Furthermore, lixel 300 receives data along respectiveI²C serial clock (I²C SCL) and serial data (I²C SDA) lines, identifiedin FIG. 4 collectively as I²C_(xy). Each of power line V_(sf) and databus lines I²C_(xy) are connected to a local microprocessor 310.Microprocessor 310 is, in turn connected individually to each of three(3) radiation sources 312 a, 312 b and 312 c.

Microprocessor 310 incorporates multiple internal Field EffectTransistors (FETs) for amplitude control of the current, and a brown-outdetector for maintaining reliability in the event of a dip in supplyvoltage. Microprocessor 310 monitors the voltage and current beingprovided to radiation sources 312 a, 312 b and 312 c and in addition toaccordingly controlling its own levels, can report its local conditionsand how it has exercised control to its associated commlink 200.Commlink 200 has electronic storage structure to locally buffer suchdata. In this way, the main control module 100 can receive informationabout how many joules of radiation energy were delivered by each lixel300, and therefore how many total joules of radiation energy total weredelivered to the area being illuminated.

In this embodiment, each of radiation sources 312 a, 312 b and 312 c isa high efficiency Light Emitting Diode (LED). Microprocessor 310monitors the current running through each of the LEDs 312 a, 312 b and312 c thereby to make adjustments to the current supply so as tomaintain a regulated current and therefore a regulated radiation output.

In this embodiment, radiation source 312 a is an LED that outputsradiation having a wavelength of about 455 nanometers (nm) (Δλ 25 nmtypical), radiation source 312 b is an LED that outputs radiation havinga wavelength of about 660 nm (Δλ 25 nm typical), and radiation source312 c is an LED that outputs radiation having a wavelength of about 850nm (Δλ 30 nm typical). The about 455 nm wavelength of radiation isprovided with a view to treating bilirubin associated with jaundice andfor reducing bacteria contamination in wounds. Furthermore, whilevisible red having wavelength near to 632 nm has been commonly used fromthe earliest He—Ne lasers to treat topical wounds and othermusculoskeletal conditions, more recently wavelengths between 650 to 670nm have been commonly used. Manufacturers have been able to createeffective strategies in doping semiconductor materials and opticalpackaging to increase the conversion rate from electrical to opticalpower.

The about 850 nm wavelength of radiation is provided with a view toachieving deeper penetration into the muscle and circulatory tissuesbecause these are more transparent to the longer wavelength ofnear-infrared. Wavelengths between 800 and 870 nm approach what iscurrently considered to be near the optimal window of transmission wherered cells and water allow transmission into tissue.

It will be noted that the 455 nm blue wavelength is a higher photonicenergy device, and its penetration is low compared to that of the redand near-infrared wavelengths.

Depending upon the instructions sent from main control module 100 viaits respective commlink 200, microprocessor 310 of lixel 300 actuatesany or all of radiation sources 312 a, 312 b and 312 c. It will beunderstood that radiation sources 312 a, 312 b and 312 c may requirerespective, different voltage levels to operate. In this embodiment, themain control module establishes the appropriate voltage level forwhichever of radiation sources 312 a, 312 b and/or 312 c byautomatically setting the V_(net) voltage level to a level appropriateto the radiation source(s) to be activated during a particular treatmentregimen, or phase thereof. Because the main control module 100 controlsV_(net) voltage level in concert with its instructions to commlinks 200as to which radiation source(s) is/are to be actuated, each lixel 300does not have to include respective voltage divider components for eachradiation source. This configuration can provide cost savings,particularly for larger lixel arrays, and can also reduce the amount ofheat that would have to otherwise be dissipated through the lixel arrayB via step-down resistors.

A therapist may program the microprocessor 110 of the main controlmodule 100 to operate radiation sources 312 on fewer than all lixels 300in the lixel array B. For example, radiation sources 312 on all lixels300 of a large lixel array B may not be required, for example inimplementations where the photoarray is being used in order to providephototherapy to a relatively small target area on a patient. Due to theindividual addressability of the lixels 300 provided by theconfigurations described herein, individualized activation andde-activation of the radiation sources 312 is possible such that powercan be preserved more readily than photoarray systems that do notprovide individual addressability.

In this embodiment, actuation of each radiation source on each lixel 300is controlled by the main control module 100 providing instructions toeach of the commlinks 200 to begin a timed sequence of messaging withthe individual lixels 300 to actuate one or more of its radiationsources 312 in accordance with a protocol. The radiation sources 312 maybe cycled ON and OFF in a predefined manner so as to prevent generatingsudden electrical transients which can cause noise in the photoarraysystem 100 itself due to electromagnetic interference (EMI), or innearby devices. For example, power to radiation sources 312 can betailored as a sinusoidal or linear ramped increase to the desiredholding level and then decreased similarly back to fully off. Theability to reduce the intensity or rapidly modulate the output is also amechanism for controlling the temperature by reducing the average ONtime of the radiation source 312. Pseudo random modulation, such as isprovided by stochastic signal density modulation, an example of which isa technology provided by Cypress Semiconductor known as PrecisionIllumination Signal Modulation (PrISM), or pulse width modulation (PWM)may be employed to achieve this. As would be understood, an LED drivenbelow 100 milliAmperes (mA) will not provide reliable or any radiationoutput. For example, in the event that the equivalent of 50 mA worth ofradiation is desired for a particular treatment or treatment phase, theLED is driven at 100 mA but modulated at an averaged 50% duty cycle soas to produce the radiation to compensate for the operatingcharacteristics and produce output as though it were being steadilyoperated at 100% duty cycle at half of 100 mA (i.e. 50 mA). Above thispoint the duty cycle can be adjusted until 100% duty cycle is reached atthe 100 mA level, and then the actual current level can be increased toproduce increases in the radiation output. In general, the relationshipbetween current and radiation output is linear above this point andwithin a range, such that 200 mA of current will produce twice the lightof 100 mA. This is effectively the PRISM technology being used withinthe PSoC (Programmable System on Chip), which is implemented as a FETcurrent driver of LEDs with programmable tables stored therein.

Such individualized control provided by the photoarray system 10described herein allows for a balanced or increased thermal conductionrate to the lower ambient temperature at the heat sink side of the lixelwhich prevents an increase in temperature on the patient side of thedevice.

Also connected to microprocessor 310 of lixel 300 is a temperaturesensor, in this embodiment a thermistor 314, and a photo sensor, in thisembodiment a photodiode 316. Thermistor 314 provides microprocessor 310with a reading of the ambient temperature level local to the lixel 300.Similarly, photodiode 316 provides microprocessor 310 with a reading ofthe ambient radiation intensity level local to the lixel 300. One ormore additional sensors 326 may be provided in order to sense ambientmotion, humidity, physical orientation, acceleration, magnetic field,proximity, audio level, video, images, one or more colours, or otherambient physical quantities for providing operating and environmentdata. The provision of such sensors in association with each or somelixels 300 enables the sensors to be distributed amongst the radiationsources. In this embodiment, as each lixel 300 includes sensors, thesensors are distributed generally uniformly amongst the lixels 300.Other configurations for distributing sensors generally uniformlyamongst the radiation sources, such as for example by providing onlyevery second lixel 300 with one or more such sensors, or for providingone type of sensor on one lixel 300 and another type of sensor on thenext lixel 300, and so forth, are possible. Other configurationsincluding non-uniform distribution of sensors amongst the radiationsources 300 may be employed in particular implementations.

Because sensors 314, 316 and 326 are local to lixel 300, microprocessor310 is able to communicate local temperature and radiation intensityreadings to a respective commlink 200 when polled by the commlink 200 tocollect and store the readings for each of the subset of the pluralityof lixels 300 with which it is associated. Such polling may be initiatedby the main control module 100, so as to collect local readings forrestructuring and/or buffering at respective commlinks 200 forsubsequent provision to main control module 100 and to, in turn, modifyactuation of any or all radiation sources 312 of any or all lixels 300in the lixel array B should local radiation intensity be too high or toolow, or should local temperature be too high, for example. In thismanner, high-resolution temperature and intensity feedback is availableto the main control module 100 so that it may, in turn, modify thesequencing and/or provide granular control over the operation of eachindividual radiation source 312 in order to provide heat management andto accurately determine the amount of radiation actually being deliveredto a patient. More particularly, it is preferred that maximumtemperature at a particular location in the lixel array B be 45° C. orlower. Furthermore, such local readings collected in this way, alongwith any automatic modifications in operation by lixel 300 or maincontrol module 100 may be stored and/or compressed and/or made availablein raw or pre-processed form to a therapist or other user via thehuman-machine interface 116, or output via RF transceiver 112 toexternal computing device 1000 for further processing or datacollection.

The multiple-tier structure provided by main control module 100,commlinks 200 and lixels 300 further facilitate efficient field-upgradesof the firmware on lixels 300. The main control module 100 can updatethe firmware on a commlink 200 and then instruct the commlink 200 to, inturn, handle upgrading the firmware on its respective lixels 300. Inparticular, the main control module 100 does not have to remain occupiedupdating firmware on individual lixels 300 as it has delegated this taskto its commlinks 200.

Turning now to FIG. 5, there is shown an isometric view of components ofa lixel 300 in exploded view. A platform 318, in this embodiment ahexagonal-shaped printed circuit board, supports and interconnects on apatient-facing side of the lixel 300 surface-mount LEDs 312 a, 312 b and312 c, the microprocessor 310, and other components such as photodiode316, thermistor 314 (which are not shown in FIG. 5), and other sensor326. A radiation diffuser 324, which in this embodiment is a translucentplastic dome, is affixed over top of at least the radiation sources 312in order to provide diffusion of the radiation being emitted over awider area thereby to enable wider coverage on the patient. On the sideof the platform 318 opposite the patient-facing side are five (5)insulation displacement connectors (IDCs) 322 a to 322 e for providingconnectivity, without line termination, to the five (5) power and datalines V_(sf), V_(netf), GND, I²C SCL and I²C SDA, respectively. Due tothe use of IDCs, spacing of lixels 300 and overall length and shape oflixel array B can be established and/or specified during assemblywithout drastic modifications to tooling. In particular, lixel arrays Bwith different sizes and spacing can be easily established by simplyestablishing the length of the five (5) power and data lines V_(sf),V_(netf), GND, I²C SCL and I²C SDA and affixing the lixels 300 with theIDCs accordingly.

A heat transfer structure, in this embodiment a heat sink 320, alsoextends from the side of the platform 318 opposite the patient-facingside for drawing heat away the patient-facing side of the platform 318.

FIG. 6 is an isometric view of the top of a portion of a series offlexibly interconnected lixels 300. As can be seen, the lixels 300 inthis series have been concavely flexed with respect to each other suchthat facing edges of platforms 318 of adjacent lixels 300, which arespaced from each other when the series is not flexed, come into contactwith each other at a contact point C, thereby to limit further flexingin a concave manner. The flexing is provided in order to enable thelixel array to be wrapped around or otherwise conformed to a subject'sbody, and the limiting provided by the physical configuration andpositioning of platform 318 and other physically interacting componentsreduces the potential for undue stress on the power and data lines, theIDCs, and other components. This concave flexing is enabled by theflexible insulated wires for each of the five (5) power and data linesV_(sf), V_(netf) GND, I²C SCL and I²C SDA each having a small amount ofslack at slack regions S, as can be seen in FIGS. 7 and 8. The concaveflexing is further limited by a fabric, non-woven material, flexiblemetal band or other thermally conductive material of sufficient strengthas a control strip 400 that is affixed to the heat sinks 320 and thatextends the length of the subset of lixels 300 in a given strip. Thehexagonal shape of the printed circuit boards provides compact nestingof lixels 300 in rows and columns in combination with the ability tophysically move with respect to each other in multiple directions (forexample not just concavely and, to a lesser degree, convexly alongstrips of lixels 300 sharing the same data and power lines, butconcavely and convexly across strips with respect to adjacent lixels300, ie. laterally and/or longitudinally). This enables conforming theoverall lixel array B to the region of the patient being treated with aview to providing uniform emission of radiation towards the area to betreated.

In an alternative embodiment, an additional control strip is providedand configured with respect to the lixels 300 to limit the degree ofconvex movement that is permitted, so as to limit the stress placed uponpower and data lines, the IDCs and other components that may otherwiseoccur if the power and data lines are permitted to easily become tautduring convex flexing.

FIG. 7 is an isometric view of the top of a portion of a series offlexibly interconnected lixels 300 encased in flexible transparenthousing 500. In this embodiment, flexible transparent housing 500 is alength of flexible plastic tubing that can be cut from a roll to aparticular desired length to completely enclose and protect the lixelarray B, and sealed to inhibit the ingress of water or othercontaminants. FIG. 8 is an isometric view of the bottom of the portionof the series of flexibly interconnected lixels of FIG. 7.

Although embodiments have been described with reference to the drawings,those of skill in the art will appreciate that variations andmodifications may be made without departing from the spirit and scopethereof as defined by the appended claims.

For example, other local conditions beyond temperature and radiationintensity can be measured by sensors associated with a given lixel, suchas current, voltage, orientation, acceleration, gyroscopic, ambientlight, magnetic field, proximity, audio level, video image and colour.

Furthermore, while a photoarray system has been described herein thatincludes a main control module 100, a plurality of commlinks 200 and aplurality of lixels 300, other configurations are possible. For example,the three-level hierarchy could be reduced to two levels (i.e., maincontrol module 100 and respective lixels 300), provided thatsemiconductors are employed that can reliably communicate over a shortrange (0.1 to 3 meters) communication channel at high speed (125 kbit to12 Mb or faster).

Furthermore, while embodiments have been described in which each lixel300 controls the power directly to the local radiation sources 312 a,312 b and 312 c, embodiments are contemplated in which an alternativelixel structure having a microprocessor 310 is capable of controllingone or more adjacent lixels that may not have a respectivemicroprocessor.

While embodiments have been described in which the lixels 300 have threeradiation sources that are LEDs, embodiments are contemplated in whichlixels have fewer or more radiation sources, emit different wavelengthsof light than those that have been described by way of example herein(such as ultraviolet radiation, violet radiation, other visible orinfrared radiation) and those in which the radiation sources are otheror various types of radiation sources such as solid state laser diodes,OLEDs (Organic Light Emitting Diodes), or FIPEL (Field-induced polymerelectroluminescent) radiation sources, with corresponding respectiveoperating characteristics and supporting circuitry, for example.

Furthermore, while in embodiments described an aluminum block heat sink320 has been shown as part of lixel 300, other configurations arecontemplated. For example, due to the open-backed nature of the lixel300, where lines for V_(sf), V_(netf), GND, I²C SCL and I²C SDA runalong the sides of the underside of the platform 318 rather than acrossthe middle of platform 318, adequate heat dispersion may be providedwithout a heat sink.

Furthermore, other embodiments of heat sink may employ a rectangularblock or a block with a cutaway portion having a rectangular, oval orcircular cross-section for receiving a heat conveyance structure such asa rigid or flexible heat pipe that can convey heat away from severallixels 300 in a row. Flexible phase change material or materials may beemployed to assist with drawing heat away from the patient-facing sideof the lixel 300. Additional or auxiliary cooling systems may beprovided.

Furthermore, while platform 318 has been described as hexagonal-shapedprinted circuit board, other shapes such as square, circular orirregular-shaped platforms may be employed.

While microprocessors 110, 210 and 310 operating at 5V are employed inthe embodiments described above, alternatives are possible. For example,microprocessors that operate at 3.3V or lower could be employed.

Furthermore, while embodiments have been described in which each lixelincorporates a temperature sensor and a radiation sensor, variations arepossible. For example, every other or third lixel could be provided withone or both such sensors. It will be understood however that localtemperature and radiation intensity can vary widely across shortdistances due to the physical attributes of the patient, clothing,adjacency, and effectiveness of local heat sinking.

Furthermore, while the main control module in embodiments describedabove provides data communications along a two-line I²C serial data bus,an alternative data communications scheme may be employed, such asLINbus (Local Interconnect Network bus), 1-Wire or some other widelyavailable or proprietary bus technology.

Furthermore, an alternative embodiment of a lixel array B couldincorporate a wireless communication link for very short range and awireless power transfer scheme such as WiTricity or Qi to accomplish thesame individual control of each lixel without the hardwired links foreven greater flexibility limited only by the typical range of thewireless power transfer.

Furthermore, an alternative embodiment of a lixel array B could includesensors 326 dispersed at relevant locations throughout the lixel arrayB. For example, for wound monitoring, a photoarray system for use inphototherapy could be provided with colour sensors distributedthroughout the lixel array B in such a way as to have colour sensingboth peripherally and centrally with respect to a wound being treated.Emission of radiation from particular radiation sources 312 could beused to cause the wound area to, in turn, emit radiation depending uponits healing state, such that the data collected by the colour sensorscould show rate and progress of the healing.

FIG. 9 is an isometric bottom view of an alternative lixel 600 for aphotoarray system, and FIG. 10 is a bottom plan view of the alternativelixel 600. Like in other embodiments, lixel 600 includes one or morethan one electrical component supported on a respective platform 618,and is interconnected with at least one adjacent such lixel 600 viaflexible wires. In this embodiment, a heat sink structure 620 issupported on the platform 618 for dissipating heat generated by thecomponents, and the heat sink structure 620 further incorporates strainresistance structure that is interfacing with, and imparting strainresistance to, the flexible wires.

In this embodiment, the strain resistance structure incorporated intothe heat sink structure 620 includes two channels 602A and 602Bextending along the heat sink structure 620. Channel 602A is defined bysidewalls 604A_1 and 604A_2, while channel 602B is defined by sidewalls604B_1 and 604B_2.

Each of channels 602A and 602B are open-ended, but each also hasmultiple entryways through a respective sidewall. In particular, channel602A has two entryways 606A_1 and 606A_2 through sidewall 604A_2,whereas channel 602B has three entryways 606B_1, 606B_2 and 606B_3through sidewall 604B2. Each of the entryways 606A_1, 606A_2, 606B_1,606B_2 and 606B_3, as well as channels 602A and 602B are dimensioned toreceive the flexible wires. The entryways are each just a small amountlarger than the width of the wires so that the wires can bear againstthem when under strain.

The combination of the channels and the entryways through theirsidewalls provide indirect pathways for the flexible wires such that,under strain, the flexible wires bear against the structures defined bythe combination of the channels, sidewalls and entryways thereby toprovide strain resistance. These structures may be seen as posts againstwhich the flexible wires can bear when under strain. As such, if thelixel 600 is moved with respect to an adjacent lixel, the resultantstrain on the flexible wires interconnecting lixel 600 with the adjacentlixel causes the flexible wires to bear against the structures ratherthan transmit all of the strain along the flexible wires to the point atwhich each wire is electrically connected to the platform 618. In thisway, the electrical connections are somewhat relieved from strain andthereby are somewhat protected from breakage, facilitating longerservice intervals. By incorporating strain resistance structure into theheat sink structure itself, significant strain resistance can beachieved in combination with heat sinking, without increasing theoverall size of the lixel 600.

In this embodiment, alternative lixels 600 and 600A in an array are notarranged adjacent to each other such that their platforms come intocontact with each other when flexed concavely to a particular point.

In alternative embodiments, the strain resistance structure incorporatedinto the heat sink structure may include one or more posts withoutelongate channels. In other embodiments, the strain resistance structuremay include only one channel, may include two channels each with onlyone entryway, or other such combinations of strain resistance structureincorporated into the heat sink structure.

FIG. 11 is an isometric bottom view of another alternative lixel 600A,and FIG. 12 is a bottom plan view of the alternative lixel 600A. Lixel600A is very similar to lixel 600. However, lixel 600A differs in thatits heat sink structure 620A incorporates a strain resistance structurewith channels 602A and 602B that both have three entryways, namely606A_1, 606A_2, and 606A_3 for channel 602A, and 606B_1, 606B_2 and606B_3 for channel 602B. As can be seen particularly in FIG. 12, theheat sink structure 620A is symmetrical. It will be understood that, asillustrated by the embodiments showing heat sink structures 620 and620A, numerous configurations of heat sink structure having variousnumbers of entryways, either the same for each channel or different, maybe employed in numerous configurations in order to provide strainresistance to flexible wires extending from connection points towardsadjacent lixels.

What is claimed is:
 1. A photoarray system comprising: an array oflixels, each lixel comprising at least one electrical componentsupported on a respective platform, each lixel in the array electricallyinterconnected with at least one adjacent lixel via one or more flexiblewires; and heat sink structure supported on each of the platforms fordissipating heat generated by the at least one electrical component, theheat sink structure incorporating strain resistance structureinterfacing with, and imparting strain resistance to, the one or moreflexible wires.
 2. The photoarray system of claim 1, wherein the strainresistance structure comprises one or more posts against which the oneor more flexible wires are positioned to bear when subjected to strain.3. The photoarray system of claim 1, wherein the strain resistancestructure comprises: at least one open-ended channel extending along theheat sink and defined by sidewalls; and each channel having an least oneentryway through a respective sidewall; wherein each channel andentryway is dimensioned to receive at least one of the one or moreflexible wires.
 4. The photoarray system of claim 3, wherein the strainresistance structure comprises two of the open-ended channels.
 5. Thephotoarray system of claim 4, wherein each of the two open-endedchannels has at least two entryways through respective sidewalls.
 6. Thephotoarray system of claim 5, wherein each of the two open-endedchannels has three entryways through respective sidewalls.
 7. Thephotoarray system of claim 4, wherein a first of the two open-endedchannels has a different number of entryways than the second of the twoopen-ended channels.
 8. A photoarray system comprising: a controlsystem; a lixel array comprising a plurality of lixels each comprisingat least one radiation source that is individually controllable by thecontrol system to emit radiation; and a sensor array comprising aplurality of sensor modules distributed amongst the plurality ofradiation sources, each of the sensor modules configured to communicaterespective local readings to the control system, wherein each of theradiation sources is supported on a respective platform comprising acircuit board, wherein each circuit board is interconnected with atleast one adjacent circuit board with a plurality of flexible wires. 9.The system of claim 8, wherein each platform supports only one radiationsource.
 10. The system of claim 8, wherein each platform supports atleast two radiation sources.
 11. The system of claim 8, wherein eachplatform comprises a circuit board.
 12. The system of claim 11, whereinthe printed circuit board has a shape selected from the group consistingof: a hexagon, a square, a circle and an irregular shape.
 13. The systemof claim 8, wherein the flexible wires are connected to circuit boardswith a respective insulation displacement connector.
 14. The system ofclaim 11, wherein each circuit board is in contact with a heat transferstructure.
 15. The system of claim 14, wherein each heat transferstructure comprises a heat sink supported by the circuit board andconfigured to draw heat away from one or more radiation sources.
 16. Thesystem of claim 14, wherein the heat transfer structure comprises one ormore tubes incorporating a liquid coolant, each tube being associatedwith a plurality of the circuit boards to transfer heat away from one ormore lixels along the one or more tubes.
 17. The system of claim 14,wherein the heat transfer structure comprises a flexible phase changematerial within a rigid or flexible container.
 18. A lixel array for aphotoarray system comprising: a plurality of flexibly interconnectedlixels each comprising at least one radiation source, each lixelcomprising a rigid platform for supporting the at least one respectiveradiation source, each platform being configured to be moved withrespect to an adjacent platform between a position in which an edge ofthe platform and a facing edge of an adjacent platform are spaced and aposition in which the edge of the platform and the facing edge are incontact with each other.
 19. The lixel array of claim 18, wherein thelixel array comprises sections of lixels, and each of the lixels in asection of lixels is flexibly interconnected with a plurality of wires.20. The lixel array of claim 19, wherein the wires have a slack regionbetween adjacent platforms.
 21. The lixel array of claim 19, whereineach section of lixels comprises a control strip associated with thelixels for limiting the extent of movement of lixels with respect toeach other.